Most larger buildings today are constructed using precast concrete piles. Typically these concrete piles are hexagonal in cross section and have lengths varying from 20 to 80 feet (6 to 24 meters), they have diameters of 12, 14 and 16 inches (305, 355 and 405 mm, nominal), between opposed flat faces, between opposed angles the distances are approximately 15, 17 and 19 inches, and weigh between 1.28 and 9.10 (short) tons (1.16 to 8.255 metric tonnes). Reinforcing metal strands, typically six in number, extend longitudinally of the pile, with a spirally wound reinforcing rod outside the longitudinal reinforcing strands.
Although the piles themselves have considerable compressive strength, the concrete only has about 35 MPa (about 5000 psi) lateral strength. After the piles have been driven into the ground they are cut off at about grade level, to provide support for a building, a floor or a concrete slab. After cutting, the top of the cut piles are pulverized to remove the concrete, while retaining the metal reinforcement intact, to allow for pouring of concrete or cement around the reinforcement. The amount of the pile which is pulverized is typically 18 inches (46 or so cm), and may be varied to comply with building codes. The piles cannot be cut to the proper size before they are driven. The piles must be cut after being placed.
Common methods of cutting piles at grade level involve the use of hydraulic concrete breakers, typically mounted on a hydraulically equipped backhoe or other construction vehicle. Alternatively circular saws, and blasting are used. Hydraulic concrete breakers tend to split the piles below grade level. The proportion of piles damaged by splitting is typically between about 1 damaged pile in 4 (25%), and about 1 damaged pile in 15 (approx. 7%). In some cities this method is not allowed by the building code. Blasting techniques to trim or cut off the top of the pile to grade level, or the use of jack hammers (pneumatic drills), are both dangerous to personnel and economically costly. None of the current methods are entirely satisfactory, and all are very costly.
It is a principal object of the invention to provide a device specifically intended to cut precast concrete piles. A further principal object of the invention is to provide an improved method of cutting precast concrete piles. Other and further objects will become apparent to those skilled in the art from the specification, claims and drawings.